Current network-based techniques for determining user location include tower-based triangulation, multilateration of the angles or times of arrivals of wireless terminal signals, signal strength based estimations, GPS-based techniques, and SkyHook/Polaris wireless techniques of estimating the signal environment of base stations and Wi-Fi points within a given area, including such signals' fading conditions.
However, methods are desired which allow the use of devices and known information about the local environment, to cross-reference with network-based information.